The invention relates generally to sockets to receive packaged integrated circuits for test purposes and, more particularly, to a test socket to receive leads of a semiconductor package such as a dual in-line semiconductor package, or DIP.
In the manufacture of integrated semiconductor circuits (ICs), the final packaged IC is generally subjected to testing such as parametric and reliability testing in harsh environmental conditions. Sockets are provided to receive and protect the leads of the IC during the test. Typically, test sockets are mounted on a printed circuit board (PCB) with a PCB providing interconnections between the ICs and test equipment.
A conventional test socket is shown in an exploded view in FIG. 1. Pins 10 having holes for receiving the IC leads are housed between a bottom plate 12 and a top plate 14. The diameter of each pin 10 is smaller at the bottom for reception in a hole 16 through bottom plate 12 with a recessed larger portion hole being configured to receive a flange on the upper end of each pin 10. Once the pins are assembled in bottom plate 12, top plate 14 is assembled to bottom plate 12 by suitable fasteners such as screws (not shown) to retain the pins in the bottom plate 12. Top plate 14 has holes 18 extending therethrough in alignment with pins 10 and configured to receive leads of an IC package. However, holes 18 are smaller in diameter than the flanges of pins 10 whereby the pins 10 are captured between the top plate 14 and the bottom plate 12.
FIG. 2 illustrates a socket, such as the FIG. 1 socket, attached to a printed circuit board (PCB) 40. To assemble the test sockets on a PCB, the pins 10 of the sockets are aligned with the conductive pads 34 on the PCB. Several screws 38 are provided through the PCB 40 and into the bottom plate 12 and top plate 14 via a holder plate 30. The leads 48 of the IC 50 may be inserted into the holes 18 to achieve the electrical connection to the pads 34 via the pins 10 and springs 36.
The socket is made from a conductive material coated with a non-conductive material. The coating of non-conductive material is to prevent shorting from one IC lead 48 to another IC lead 48.